This invention relates to a beverage powder which, when dissolved in a liquid, progressively increases the viscosity of the liquid. The beverage powder may be used in the preparation of liquid meals having extended glycaemic response. The liquid meals may be used in weight loss programs, to enhance athletic performance, by diabetics and to control blood cholesterol.
Foods which have reduced glycaemic response have many applications. One of these applications is the induction of satiety. Some foods are more effective in reducing hunger than others. Protein has a larger effect than either fat or carbohydrate in satisfying appetite. This has led to use of the protein sparing modified fast in weight control, a protein rich diet in which carbohydrate is almost absent. Further it appears that hyperinsulinemia is an important factor for increasing hunger and food intake. Significant reduction of size of the next meal has been achieved when the carbohydrate source was fructose only. This reduction is suppressed as soon as glucose, sucrose or starch is present. Therefore, to reduce hunger, the metabolic response to a carbohydrate load should be minimised as much as possible.
The glycaemic response to food is also an important factor in the nutritional control of diabetes. Being able to reduce the glucose and insulin responses in plasma after a meal will enable better control of diabetes. Hence another application of foods which have reduced glycaemic response is in the nutritional control of diabetes.
The most important attributes of soluble fibre are its potential for lowering postprandial glycaemia and insulin response and its ability to decrease plasma cholesterol. For example, Jenkins et al., 1978, Br. Med. J., 1, 1392-1394 have shown, that soluble fibre was most effective in reducing the rise in blood glucose and insulin when it had the highest viscosity. The most effective soluble fibre studied was guar gum. Wood et al.; 1994; Brit. J. Nutr., 72: 731-743 have determined that increasing dose of oat gum reduces plasma glucose and insulin responses. Oat gum is an oat extract which is composed mainly of the polysaccharide β-glucan. Further, reduction of the viscosity of oat gum by acid hydrolysis reduced or eliminated the capacity to decrease postprandial glucose and insulin levels. Peak plasma glucose response was inversely related to the logarithm of the viscosity of the solution. The biggest attenuation was reached with a viscosity of more than 1500 mPa·s, the level obtained with 1.4% oat gum (or 1.2% β-glucan). This viscosity is considerable and would make any drink practically unpalatable. Consequently, Wood et al. tested a powder of oat gum which was agglomerated with maltodextrin, and when added to a drink developed viscosity progressively. Such a powder is commercially available under the name INSTAGUM® (Zumbro Inc, Hayfield, Minn., USA). This powder is an agglomerated mix of oat gum and maltodextrin (ratio 1:4). A similar powder is described in U.S. Pat. No. 5,476,675.
While these powders are effective in reducing glucose and insulin levels in plasma, the beverages produced from them become very viscous, very quickly. For example, a beverage produced by dissolving the INSTAGUM® powder in liquid at a concentration sufficient to have an effect on glycaemic response, has a viscosity about one half of the maximum viscosity within 3 to 4 minutes. Ordinarily, a viscosity of about one half of the maximum viscosity would make the beverage too viscous to be palatable. Hence the beverage must be consumed immediately after reconstitution.
It is therefore an object of this invention to provide a beverage powder which, when dissolved in liquids, results in a beverage with progressively increasing viscosity.